Supportive mobile devices for animals functionally disabled have been known to the art of veterinary medicine for many years. Dogs and other household pets sustain traumatic injury of soft tissue, bone, and/or neural elements resulting in functional disability. Disabling medical conditions include inherited degenerative disorders, disc rupture, and primary diseases of the nervous system. The art has been successful in providing suitable supportive devices allowing animals to enjoy a self-sustained mobile life. Return of mobility to disabled animals reduces the risk of secondary medical problems and improved the mental health of the animal.
Applicant has developed mobile suspensory apparatuses for supporting the rear quarters of disabled animals. For example, U.S. Pat. No. 3,406,661 discloses a cart having a vertical standard extending upward in a loop from an axle having two wheels. A length-adjustable yoke member is attached to the standard at or near the natural height of the animal""s hips, and a hip support member comprising two attached horizontal loops made from a single rod, through which the animal""s legs are inserted, is attached to the standard slightly above the yoke member.
A similar two-wheeled apparatus having side rods for connection to a harness is disclosed in U.S. Pat. No. 3,215,117 (Short). The Short apparatus supports the animal""s rear quarters at its abdomen, and the side rods position the wheels at a predetermined distance from the harness.
Alternate approaches are illustrated in U.S. Pat. No. 3,241,851 (Dingbuam) and U.S. Pat. No. 2,546,726 (Creamer, Jr.). These patents teach apparatus which employ the animal""s body itself as a large part of the support structure. Both teach attachment of wheels to injured animals in a manner reminiscent of the attachment of training wheels to a bicycle.
At the other extreme, U.S. Pat. No. 2,976,840 (Hugus) discloses a complete structure having four casters and associated structure supporting a sling which both encloses and supports the animal. The animal""s rear legs are allowed to hang through holes in a sling.
In U.S. Pat. No. 4,777,910 (Pecor), there is a two-wheel passive therapeutic exercise device providing non-weight bearing motion of the rear limbs. The rear feet are placed in boots attached to a crank-arm mechanism. A striding passive motion of the rear limbs is provided by mechanically geared energy derived from the back wheels. Passive movement of the disabled rear limbs is provided by the dog walking on the front limbs.
All of the foregoing patents are intended to assist mobility by the animal pulling itself along by its front legs while the rear quarters are supported in a two-wheeled device. U.S. Pat. No. 4,375,203 teaches an apparatus for the totally paralyzed rear limb animal. Flaccid full extension of the rear limbs results from this disability. Support height required for raising the extended rear limbs creates a stressful forward angulation on the shoulders of the animal. Flexion of the rear limbs is provided by tibial sling support allowing level walking position of the body. Secondly, balanced weight distribution between front and rear quarters by adjustable horizontal positioning of the axle through a plurality of holes in 2 axle blocks. Providing flexion of the rear limbs by means of slings allows leveling of the body to a normal walking position. An adjustment of axle wheel position horizontally achieves proper weight distribution between front and rear quarters reduces stress to a minimum while the animal is walking.
The art of animal cart design has centered on the use of rear limb, two-wheeled supportive carts. U.S. Pat. No. 2,970,840 (Hughes) discloses a complete structure having four casters and associated hammock support, which both encloses and supports the animal. The animal""s rear legs are allowed to hang through the holes in the hammock structure. Lacking such embodiment as adequate wheel size for ease of function, directional control, or means of adjustment restricts the functional value of the Hughes invention.
The objective of this invention is to extend independent wheel support for both rear and front quarters in contrast to prior art units. Self-sustained mobility requires that at least partial weight bearing must be present in either the front or rear quarters. Front and rear wheel supporting elements can provide either front or rear quarters as a source of mobility. Extending the source of mobility expands the categories of disabilities assisted, such as forelimb amputees, forelimb birth defects, or total rear paralysis accompanied by forelimb weakness.
A mobile prosthetic apparatus for disabled four-legged animals generally includes a cart having a chassis wherein the chassis frame has oppositely located walls. Primary wheels are mounted to the frame at the rearward end of the frame while secondary wheels are mounted to the forward end. Each of the secondary wheels is swively mounted. In one practice of the invention a yoke is mounted to the forward end of the frame at the top of the chassis. The yoke has a first position which is connected to and spans the frame sidewalls. The yoke is movable to a second position so as to leave the space between the frame walls unobstructed by the yoke and thereby facilitate an animal being placed in or removed from the apparatus.
The chassis may be in the form of two subassemblies wherein a front subassembly includes both the forward portion of the frame and the secondary set of wheels, as well as a yoke when included in the apparatus. The second subassembly is a rearward subassembly having the rearward portion of the frame and the primary wheels. Both subassemblies are detachably connected together so that, for example, the rearward subassembly may be used independently as an apparatus for disabled animals not requiring the full benefits of the apparatus when both subassemblies are connected together.
Preferably the chassis frame is made of various tubular members which are adjustably connected together to provide for height, length and width adjustment so as to conform to the specific size of a particular animal. Tubular members are also lightweight. Various support straps or slings and leg supports may also be provided.